update

Author: realdennis

src/voting-algorithm/majority-element-ii.ts

@@ -0,0 +1,35 @@
+export {};
+function majorityElement(nums: number[]): number[] {
+    let cand1 = 0,
+        cand2 = 0,
+        vote1 = 0,
+        vote2 = 0;
+
+    for (const num of nums) {
+        if (num === cand1) vote1++;
+        else if (num === cand2) vote2++;
+        else if (vote1 === 0) {
+            cand1 = num;
+            vote1 = 1;
+        } else if (vote2 === 0) {
+            cand2 = num;
+            vote2 = 1;
+        } else {
+            vote1--;
+            vote2--;
+        }
+    }
+    // now below process pick the 2 majority candidates, let's re counts their vote
+    vote1 = 0;
+    vote2 = 0;
+    for (const num of nums) {
+        if (cand1 === num) vote1++;
+        else if (cand2 === num) vote2++;
+    }
+    return [
+        [cand1, vote1],
+        [cand2, vote2],
+    ]
+        .filter((entry) => entry[1] > Math.floor(nums.length / 3))
+        .map((entry) => entry[0]);
+}

src/voting-algorithm/majority-element.ts

@@ -2,7 +2,7 @@ function majorityElement(nums: number[]): number {
     /**
         Voting algorithm
         
-        For initial, we can have assume first candidate (nums[0]) get the votes = 1 (means one vote)
+        For initial, we can have assume candidate is 0, and vote = 0. (0 is not the input, so it'll be replace)
         
         Then iteration, if there's another item (!==candidate) we decrease the votes, otherwise increase.
 		
@@ -11,14 +11,18 @@ function majorityElement(nums: number[]): number {
         This algorithm could be proven that if there's a candidate has the least N/2 vote, it could not be elimate by other candidates.
         
     **/
-    const N = nums.length;
-    let candidate = nums[0],
-        votes = 1;
+    let candidate = 0,
+        vote = 0;
 
-    for (let i = 1; i < N; i++) {
-        if (votes === 0) candidate = nums[i];
-
-        votes += nums[i] === candidate ? 1 : -1;
+    for (const num of nums) {
+        if (num === candidate) {
+            vote++;
+        } else if (vote === 0) {
+            candidate = num;
+            vote = 1;
+        } else {
+            vote--;
+        }
     }
 
     return candidate;